Last night's Vote for a Change rally in Westminster Central Hall launched the campaign for a referendum on a new voting system, to be held at the same time as the next general election. An alliance of a wide range of parties and groups was there: odd to see Lib Dems, Greens, climate change activists, pensioners groups, votes-at-16 campaigners, fair traders and a plethora of others sharing a platform with a Ukip MEP. Who wasn't there? The two old parties whose stranglehold on Westminster is only maintained by the first past the post electoral system – though Labour has always had some reformers, and John Denham spoke for them. Not one Tory can be found, alas, in or out of the Commons.

KT Tunstall and Billy Bragg sang, and Blur's drummer Dave Rowntree made a foot-stamping speech. This campaign can only work if it can galvanise all the popular anger against the current political system and direct it towards an unstoppable demand for constructive change. Can it be done? It's a tall order in a short time. If you support it, text Change to 60013 and recruit as many others as you can. Go to the website for news on events being set up around the country. Help is needed now.

I asked CiF posters to send in questions for the Vote for a Change platform and these were chosen. Here they are, with a few answers:

ABasu asked: "What does the panel think about making voting compulsory?" Peter Tatchell replied: "No. If politicians can't persuade voters, then voters have a right not to turn up." Dave Rowntree (though Blur's drummer, he is now a Labour candidate, radical rat-joins-sinking-ship), says: "No. It sounds too Soviet to me. I'd go for votes at 16, get people used to the habit of voting young." Ken Ritchie, head of the Electoral Reform Society: "I'd want no part in forcing people to vote, especially under the present system where most people's votes are useless anyway. I want people to vote because it's important, not because they'll be fined if they don't."

Davidabsalom asked: "How can you get MPs to have more allegiance to their constituency than their party?" DeadTapeCollector's question amounted to the same: "Are there any proposals for the removal of an MP by their constituents?" Tatchell replied: If 30% of constituents sign a petition, the MP should have to submit themselves to a vote. Rowntree: PR would go some way to help, especially with STV [single transferable vote] in multi-member constituencies, where several MPs compete to represent their voters. Ritchie: Under PR if your MP is, say, some fox-hunting Tory, at least you have another choice, either with STV or with the AV-plus system, where you can choose someone else from an open list.

WheatfromChaff asked: "What would be the question asked in such a referendum?"

Tatchell and Rowntree said: Ask two questions on the referendum paper. First, should there be a change in the voting system so the number of seats more closely corresponds to the number of votes? The second question lays out several options including STV and AV-plus.

Ritchie said: Politicians will be partisan, so we need a citizens convention to hear all the evidence and choose the best questions for the referendum ballot paper.

Sign up now! No pressure for change will come from parliament, where the beneficiaries of the present system sit.

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The row over MPs' expenses and the role of the Commons Speaker has led to widespread sentiment that an entire political class has been discredited. There is now a growing recognition that no return to 'business as usual' in Westminster is possible: the machinery of representative democracy, legislature and the executive is dysfunctional and ripe for reform.

Public dissatisfaction with politics and politicians has never been greater in modern times: a national debate is needed on what must change. Columnists and commentators from the Guardian and Observer make their suggestions, but in keeping with the new spirit of the age, this is about creating an open forum: join the conversation on political renewal